Tom Lat/Lon: 34.59°N 86.74°W Elevation:600 ft
Quote:... this is done is by observing the reflected spots from a collimated light source...
Celestron 8SE Dobstuff 13.1": Swayze refigured Coulter mirror, 6 pt mirror cell (2 pt edge support) and CF focuser board made by me StarBlast 4.5 ST80/PortaMount II Zhumell 20x80/Oberwerk 15x70 on a Seronik-style tripod boom mount Hubble Optics 18 inch F/4 mirror.
Quote:The simplest technique I can think of for achieving proper lens centration involves a laser.Place the negative component on a turntable. Position a laser well above the lens, and adjust table and/or lens so that when the lens is spun, the reflected spot(s) is/are directed right back into the laser's collimating lens. Lock things down. Cement the convex element, adjusting laterally so that its spot is coincident with the other(s).I should add that the radii of curvature of one or more lens surfaces will dictate how far away you can position the laser before the spot becomes enlarged too much. But I should think that a distance at least as great as two doublet focal lengths should be far enough for sufficient precision.The laser should have a white screen (of card) attached to the front, with the smallest hole which passes the beam. This will facilitate alignment.
Quote:Easiest in terms of technique is probably the Norland UV curing adhesive. Home Depot sells black light compact fluorescent bulbs that work in a mechanics light within 5 to 10 minutes to set and an hour to fully cure.Dave
Refractors Reflectors Two Cats A few eyepieces
Inventor of the Herschel Wedgie. Watch your back.
Astronomy - The World's Second-Oldest Profession.
"You don't know Swift from Astrola." -C.H.-